Polygonal patterned ground
Videos
Polygonal, patterned ground is quite common in some regions of Mars. It is commonly believed to be caused by the sublimation of ice from the ground. Sublimation is the direct change of solid ice to a
A similar process occurs on Nile crocodiles. Their snout skins crack during embryo development, forming polygonal patterns.
Wide view of crater containing polygons with frost in the low parts, as seen by HiRISE under the HiWish program
Closer view of polygons with frost in the low parts, as seen by HiRISE under the HiWish program
Close view of polygons with frost in the low parts, as seen by HiRISE under the HiWish program Circular shapes are also visible.
Dry ice
Videos
Dry ice is the solid form of carbon dioxide. It is commonly used for temporary refrigeration as CO2 does not have a liquid state at normal atmospheric pressure and sublimes directly from the solid sta
Subliming dry ice pellet, with white frost on the surface
Dry ice being used to cool beverages in Central Park, New York
Sublimation
Dry ice in water